Portable dishwashing machine



W. l. KNAPP PORTABLE DISHWASHING MACHINE May 11, 1954 4 Sheets-Sheet 1 Filed Dec. 17, 1948 [ll/7V EN TOR. BY Zl/adu,

ATTORNEY M y 1, 1954 w. I. KNAPP 2,678,050

PORTABLE DISHWASHING MACHINE Filed Dec. 17, 1948 4 Sheets-Sheet 2 IN V EN TOR.

ll/mum aw E 7 m W A TTORNEY May 11,1954 w. l. KNAPP PORTABLE DISHWASHING MACHINE 4 Sheets-Sheet 3 Filed Dec. 17, 1948 INVENTOR. 2am ix/M BY ATTORNEY W. l. KNAPP PORTABLE DISK- WASHING MACHINE May 11, 1954 4 Sheets-Sheet 4 Filed Dec. 1'7, 1948 INVENTOR- WALTER .ZIK/VAPP BY W 47 @9 4 14 TTOR/VEV Patented May 11, 1954 UNITED STATES PATENT OFFICE 17 Claims.

This invention relates to dish washing machines, and has particular reference to a device of that character which is portable, or may be built-in as a permanent installation in a kitchen or the like.

An object of theinvention is to generally improve dish washing and rinsing machines, and to provide a machine which is simple in construction, economical to manufacture and maintain, and highly efiicient in operation because of its novel shape and construction.

Another object of the invention is to provide a dish washer which is compact, yet provided with a maximum dish andsilverware capacity, and one which may readily be used on a conventional, domestic kitchen sink drainboard, and counter top, and when'not in use, may be rolled to a storage position beneath the wall cabinets.

Another object of the invention is to provide a dish washing machine which has a high degree of portability, and which is provided with means for rolling the device from one position to another, and means for locking the device in any predetermined position.

Another object of the invention is to provide a dish washing machine which is constructed witha cambered wall housingwhich is arranged to assist in imparting a highly effective swirling action to the water.

Another object of. the invention is to provide a dishwasher having a heat activated bi-metal element which controls a spring loaded variable pitch blade type impeller, which together with the other features of the device imparts a highly effective change of pattern action to, the water, with a result that there are no blind spots in the washing and rinsing operations.

Another object of the invention is to provide a dish washing machine which is constructed and arranged with rotatable and tiltable trays, which may. be removed. from the dishwasher with the dishes remaining in the trays to facilitate the easy storing of the dishes in. the cupboard afterthe dishes have been washed anddried.

Another object of the invention is to provide a device of the character indicatedinwhich the rotatable and oscillatable dish trays are automatically oscillated and tilted. by thermostatic means, or may be, manually operated-if so desired to effect different positions of the dishes during the washing andrinsing operations;

Another object of the inventionis to provide a dishwashingmachine in which the dish trays are slidably supported on tracksprovided for. them, whereby the loaded trays may readily be removed from the machine, there being locking means for securing the trays on the tracks and means for keeping the cups and dishes inpredetermined positions on the trays.

Another object of the invention is to provide a dish washing machine having an immersionheating element incorporated therein to quickly increase the temperature of the water introduced into the machine for efiicient dish washing operation, and to control the action of the bi-metal line of the dish water, and to provide a fresh water bypass for external use at the sink while the dish washer is connected to the water tap, and to provide an efficient electrical ground contact with the water faucet while the machine-is in use.

Another object of the invention is the provision of a dish washing machine which is provided with a non-loading sediment screen which isself cleaning during the draining cycle.

Another object of'the invention is to provide a dish washing machine having a built-in sump incorporating therein an efiicient andreadily accessible cleanout plate.

Another object of the invention is to provide a dish washing machine which is constructed with a maximum capacity drain outlet including a right or left hand reversible telescoping drain spout for discharging the dish water into the sink.

Another object of the inventionis the provision of a dish washing machine having an internally discharging detergent applicator arranged:

to deposit the detergent near the center of the impeller actuated water surge, whereby to increasethe speed of dissolution of the detergent, and to facilitate the refilling ofsaid'detergent applicator.

Another object of the invention is-to provide a dish washing machine having means to facilitate its permanent installation into conventional .base cabinets and sink cabinets .by prov-iding readily accessible standard pipe fittings in the water intake and the sump.

Another object of the invention is to provide a dish washing machine having a tightly sealed' and hinged drop open type front wall to provide convenient loading of the machine when positioned on a sink, drainboard, or counter top.

Another object of the invention is to provide a dish washing machine having an audible measuring overflow pipe assembly to facilitate its use when permanently installed in a conventional base or sink cabinet.

The foregoing and other objects and advantages of the invention will become more apparent as the description proceeds, reference being made from time to time to the accompanying drawings, forming part of the within disclosure, in which drawings:

Fig. 1 is a top plan view of the device embody ing the invention with parts broken away to illustrate the relation of other parts.

Fig. 2 is a front elevational view with parts in section, and taken substantially on the line 2-2 of Fig. 1.

Fig. 3 is a bottom plan View of the device illustrated in Fig. 1.

Fig. 4 is an enlarged fragmentary detail in section taken substantially on the line 4-4 of Fig. 3.

Fig. 5 is an enlarged fragmentary detail in section taken substantially on the lin 5-5 of Fig. 3.

Fig. 6 is a vertical section taken substantially on the line 66 of Fig. 2.

Fig. 7 is an enlarged fragmentary detail in section taken substantially on the line 7-1 of Fig. 3.

Fig. 8 is an enlarged top plan view of the automatic thermostatically controlled oscillating impeller.

Fig. 9 is an enlarged view in elevation of the thermostatically controlled impeller shown in Fig. 8 with parts broken away to illustrate the interior of the impeller hub.

Fig. 10 is an enlarged view in elevation of the impellerwith parts broken away and turned substantially 90 degrees from the position shown in Fig. 9.

Fig. 11 is an enlarged fragmentary detailin plan view of the bottom of the device showing the electric thermostatic tray oscillation control with the manual control and setting lever.

Fig. 12 is an enlarged fragmentary detail with parts in section showing the tray oscillating control mechanism, the heating element, and the bimetal coil taken substantially on the line I2-I2 of Fig. 11.

Fig. 13 is a section taken substantially on the line I3I3' of Fig. 12, showing the limit control switch in linkage for the thermostatic mechanism.

Fig. 14 is an enlarged plan View of the sediment screen.

Fig. 15 is'a side elevation of the sediment screen illustrated in Fig. 14 with parts broken away to more clearly illustrate its construction.

Fig. 16 is a perspective'view of the thermostatically controlled impeller with dotted lines showing the degree of impeller blade oscillation. Fig. 17 is a plan view of one of the slidably removable dish carrying trays with dotted lines to illustrate the degree of rotation.

Fig. 18 is a section taken substantially on the line Iii-48 of Fig. 17 with dotted lines to illustrate thedegree of the tilting action of the tray. Fig. 19 is a side elevational view of the de- :1 ing and rinsing operations.

vice shown in Fig. 17 with lines dotted in to show the degree of rotation and tilt.

Fig. 20 is an enlarged fragmentary detail taken substantially on the line 2fl2fl of Fig. 6 illustrating the audible measuring overflow pipe assembly.

Referring now more particularly to the drawings, it will be understood that in the embodiment herein disclosed, the reference character It indicates the tank, or housing, of the dish washer, which is shown in Figs. 1, 2, 3, 5, 6 and 7 as resting on a sink drainboard Hill. The tank ii) is provided at the top with a removable cap II which is adapted to cover a central opening I IA, which is provided for the motor assembly as hereinafter described.

A handle I2 is positioned at either end of the tank In so that the device may be lifted. A baffled opening it is positioned at one end of the tank Ill beneath the handle I2, and serves as a ventilator for the interior of the tank, and allows the escape of steam and acts as a vacuum break in the event of possible siphoning back of dish water from the tank It into the inlet pipes.

Hooks It and I5 are provided on the rear exterior of the tank I0, and serve as means to support the hose and extension cord elements hereinafter described.

The front of the tank In is closed by means of a drop down front wall IE5 which is sealed by means of a gasket I! and locked by means of a suitable tongue latch I8. Hinges Is connect the bottom of the wall It with the tank It, and permit the wall to be dropped so that the interior of the tank It may be loaded with dishes as hereinafter described.

A drip bafile 48 (Fig. 6) deflects the water out of the cambered section of the wall it, and allows any condensed water on the wall to drain back into the interior of the tank It.

The rear wall of the tank If! and the wall It are cambered in order to increase the effective swirling action of the water during the wash- The bottom I 33 (Fig. 3) of the tank It is inclined as at IEC to form a hopper like structure which slopes to ward the center. The bottom IEIB of the tank It rests on an integral base 25! which serves asa housingfor the sump and the ball casters 2| (Figs. 2, 3 and 5) hereinafter described.

The ball casters 2i (Fig. 5) are mounted in suitable fittings ZIA which. are threadedly mounted in adjustable plates 2.2 which are secured to the under surface of the bottom I933. The casters 2| are sheathed in cuplike members BIB, the lower ends of which are protected by rubber elements 24 which serve as shock absorbing, non-skid elements when the device is in operation. The ball casters are spring loaded, as at 23.

In order to prevent the shifting of the dish washer on the sink drainboard ISA (Fig. 7). I provide a friction brake 25 which is eccentrically pivoted, as at 25A, to a bracket 28, which in turn is secured to the base to. A brake handle 26 is secured to the eccentric brake 25, and extends to the exterior of the device so that the brake 25 may be rotated into and out of locking engagement. A suitable anti-friction tread 2! encompasses substantially the lower one-half of the periphery of the brake 25. v

An extension cord 29 extends through a suitable opening formed in the rear wall of the tank I0, and connects the motor assembly hereinae zspso after describedto a suitable source of electrical power. A flexible metal hose 3*!) comiects to a suitable fitting 30A which in turn communicates with the interior of the tank I B, and to a conventional water tap 308 through means hereinafter described. The metal hose 38' is electrically grounded for the purpose of protecting the user of the dish water from possible electric shock.

mterposed between the water tube 303 and the flexible hose 3|! is a specially designed automatic by-pass and anti-back pressure valve 32, which is provided with a spring loaded ball and a by-pass cook 34, whereby water may be drawn directly from the tap 303.

The fitting 30A communicates, among other elements, with an overhead rinsing conduit 35 which in turn communicates with a cone spray nozzle 35 arranged to direct a powerful spray to the front of the plates, and a fan spray nozzle 37 which is adapted to direct the spray against the top of cups and cone spray nozzles 38 and 39, which are arranged to also direct sprays to the dishes and glasses carried in the trays as hereinafter described.

A fan spray nozzle 40 is arranged to direct a spray to the top of plates, and cone spray nozzles 4|, 42, 43 and M also communicate with the conduit 35, and are arranged to respectively spray the dishes in the right rear tray, the silver basket, and the left rear trays as hereinafter described.

The applicant desires to emphasize the importance of the above described overhead rinsing arrangement, which is not only useful in the pre-rinse operation, but is particularly effective on the final rinse which is necessary to knock off the final food sediment which often remains on the dishes in conventional impeller rinse operations.

The flat dishes are held in individually removable, wire trays and racks 90, as, 91 and Hit, which are arranged so that each oscillates in an are about its own axis, while at the same time the axis is given a rocking motion. The trays and rocks slide in and out of the tank it on. rods 93 and I60. Cups are held in a tilted position on removable racks I94 and I95 which are equipped with flexible cup tilting rods Ill -lA.

The racks I54 and H35 slide in and out on tracks Hi8 which are held in position for loading by a pivoted latch I08, and are arranged toswing bacl: and up and be held in locked position by IQ'I. Water glasses are supported on the removable tilted rack IDS-and a hook III! which comprises part of a swing bracket IIZ which is adapted to support the silver ware basket I I I,

the latter being formed of metal having variable size holes pierced therein, the said basket being provided with separate and different depth together by means of an arm I 5 having postsiififi and H53, which are adapted to engage slotted and hinged hasps 92- and 99. The oscillating and rocking motion is transferred from rack to to rack' 54 by means of a loop coupling 96 (Fig. 1') The oscillating and rooking motion is transferredfromrack 9'Ito rack Itll through the loop coupling I93 (Fig. 1).

Secured to the'arm 5- is a shaft In, which shaft is adapted to be rotated by means of a bimetal coil ribbon II8' which is arranged to be flexed by means of heat generated in electrical heating element I211. The heating element I253 is controlled by means of an electrical switch I 25, which is alternately opened and closed by means of a rod I23, which is slidable inthe' walls of the housing HQand which is actuated by the arm I22 secured to the lower end of the shaft Ill. The arm I 22 is slotted to engage the rod I 23 which carries limit elements I24 and H5. When the limit element I 24 is contacted by the arm I22, the rod I 23 moves to the right turning off the switch 25. This permits the bi-Inetal ribbon H8 to unfiex returning the arm I22 to the left. When the limit element H5 is reached, the switch 526 is turned on and the operation repeats, and is automatically continued through the dish washing operation. This action provides a smooth oscillation of the racks without danger of damage to or rattling of the dishes.

The bottom I 63 (Figs. 3 and 4) is provided with a drain sump 58 which communicates with a telescoping drain tube 58 through which the tank may be drained into the sink. The drain tube 52% is mounted for left and right hand operation. The sump 59 is fitted with a threaded cleanout plate 55, which is screwed into the bottom of the sump 58 and is easily removed by inserting a spanner wrench in the holes 55. A pipe size threaded flat plug 5'7 is screwed into the cleanout plate 55, the latter to accommodate a standard drain pipe for stationary or built-in installation. A drain plate 5i covers the sump 5i! and is adapted to belifted by a cam 52 carried at the end of the rod53.

It is desired to call particular attention to the comparative ease of removing the cleanout plate 55, simply by turning the dish washer on its side rather than having to go through many parts to get at the drain sump 50, as is the case in most conventional dish washer equipment.

Positioned on top of the drain plate 5! is a nonclogging sediment screen 55 (Figs. 2, 6, l4- and 15) which is constructed as follows:

A ring B tA and straps 84' are secured to the plate 5I by rivets 84B; and support the screen. The screen is formed of a sheet of perforated metal with see-saw shape side walls 8i, and a dropapron 85. The apertures in the screen vary from comparatively small apertures 83 around the bottom to much larger holes 35 which are positioned in the see-saw side walls tI.

In operation, sediment lodges in the crevices formed by the see-saw shape of the side walls permitting water to flow each side of the ment, which sediment remains in the crevices until the flushing action takes place in the drain ing of the tank IE.

The construction of the see-saw walls 8i and the hole size variationin the screen permits water to pass through the screenin spite of the sediment load, thereby assuring suiiicient water for the impeller surge.

An overflow cap Mi (Fig. 20) is threadedly secured, as at itA, tothe-bottom 25B and cominunicates with a channel All, which in turn connected to the drain sump 5s; The overflow fi lias a side opening dtB and measures the cor* rect amount of water to be left in the tank It? for the diiferent washing and rinsing operations. A water spinner 430 is rotatably secured to the inside of the cap 4d,.andis adapted to beimpelled by water flowing through the cap, and is arrangedto impinge on a reedicED. to effect an audible signal indicating a properly filled tank. This audible signaling device is particularly advantageous when the dish washer is permanently built-in to a sink cabinet or the like.

A detergent dispenser cup 65 is mounted on an arm 65A which in turn is secured to a rod 67 rotatably mounted in suitable brackets 67A which are secured by any suitable means to the outside of the motor chamber 63. The dispenser cup 65 is adapted to be tripped by means of an externally positioned knob 66, which connects to suitable linkage 69 which is slidably secured to an arm 69A carried by the rod 61.

The dispenser cup 65 is covered by means of a rubber stopper EB which swings out after the cup 65 is tilted allowing the detergent contents to be spilled into and near the center of the water surge at the start of the washing cycle. I have found that the detergent is more quickly and completely dissolved when it is injected. near the center of the water surge generated by the impeller 10.

A spherically terminated, vertically elongated motor chamber 63 is mounted in the opening i he of the housing, and contains a suitable electric motor 66, which is electrically connected to the lead 29, and has a shaft 6! which is adapted to actuate an impeller 'lll which is constructed and arranged as hereinafter described.

The chamber 83 is provided with a stuiiing box 62 which is adapted to prevent water from entering the interior of the motor chamber 63. A suit able timer clock (not shown) is enclosed in a water tight housing I21 (Fig. 3) which is mounted on the bottom IUB of the tank iii, and is controlled from the front of the tank by a knob i251 and a rod l28. This timer clock is electrically connected to the motor and is adapted to shut oil the electric motor at a predetermined time.

The impeller 70 (Figs. 2, 8, 9, l and 16) mounted at the end of he motor shaft iii con" sists of two blades H and 12 which oscillate as herein described to effect a varying surge pattern in the water contained in the tank It. This variation in surge pattern eliminates entirely the blind washing spots which occur in presently known dish washing devices. The blades ii and T2 are respectively mounted off and on center which adds to the irregularity of the water surge pattern. The rising and falling of the temperature in the surrounding water or air causes the blades to automatically oscillate as herein described varying the angle of and shape of the water surge, and the result of the spray on the dishes. It will be noted by dotted lines ii and i2, Fig. 16, the different positions taken by the impeller blades H and 12 on their respective axes i3 and M. This up-and-down action is imparted to the blades through axis shafts and gears '13 and i l, by the coiling or uncoiling of the bimetal 75, Fig. 9, which coiling or uncoiling is controlled by the rising or falling of the temperature of the surrounding water or air. The above thermostatic action does not directly control'the speed of rotation except as a by-product of the changed angle of the blades, the motor might speed up or slow down slightly, but it does definitely control the varying angle which the impeller blades assume at the different ambient temperatures. The thermostatic bi-metal controls the varying angle of the impeller blade settings.

The detailed construction of the impeller iii is shown in Figs. 8, 9 and 10 in which ii indicates the center heel connected blade and 12 the oilcenter heel connected blade which cause the unsymmetrical changing surge and spray pattern with a differing speed of angle change between the respective blades. The impeller is provided with a hub T! which is axially bored to accommodate the motor shaft 6i to which the hub is secured by set screws 19. A counter bore ll-A extends through the remainder of the hub H and is arranged to accommodate pinions l3 and M which respectively operate the blades H and 72.

The teeth of the pinions l3 and 14 mesh with one another causing the blades H and E2 to rotate in opposite directions continuously changing the angle of the water surge. The pinions l3 and '14 are actuated by a flexing bi-metal strip #5, one end of which is attached to the bottom of the hub Ti, and the other end of which is attached to the shaft MA. As the temperature of the water surrounding the impeller hub ll rises or falls, the bi-metal strip l5 flexes and unfiexes causing the pinions to be actuated changing the angle relation of one blade with reference to the other. In

order to reduce vibration and eliminate the possibility of excessive angle travel, a spring it is mounted on the hub I? and engages the walls of slot 76A (Fig. 9).

In order to boost the temperature of the water from conventional water heating sources to that desired in successful mechanical dish washing, and to stimulate the action of the bi-metal controlled impeller blades H and i2, I provide an immersion heating element 8! which is installed close to the bottom of the tank Ill and surrounds the lower part of the impeller H3. The heating element 6'! is of conventional make and is electrically connected to the electrical inlet 29.

A conventional clock timer is mounted in a water tight housing i3!) positioned on the bottom Hi3 and is adapted to control the heating element 81, and is arranged to be set by a rod l3! at the end of which is a knob i32.

I will now describe a complete operating cycle of the dish washer:

The machine is placed upon the drainboard 49A, or counter top, or a table adjacent to the sink within reach of an electric outlet. The swivel hose connection 32 is attached to the sink faucet 30B, and the extension cord 29 is plugged into the electrical outlet.

The shallow dishes are placed in racks as, 84, 9'5 and NH. The cups are placed in trays Hi4 and H15, and water glasses are placed in rack H39 and on the basket bracket Hi). The silverware is placed in basket l I, and the basket and all of the trays are then inserted in the tank iii. Inasmuch as the racks, trays and silverware basket are removable and portable, it is, more convenient to load them outside of the dish washer and then insert them fully loaded in the machine for the washing, rinsing, and drying operations.

The detergent cup 65 in its untripped position is moved toward the front of the dish washer by means of the knob 54, and rod 5?. The cup is then loaded and moved rearwardly where it is ready for use.

The front wall I6 is closed and with the drain plate 5! in open position, hot water is introduced to the dish washer through the hose 3i], and the over rinse pipe 35. The hot water is permitted to enter the dish washer through the over spray nozzles'for approximately 30 seconds. This serves as a pre-rinse washing down and out through the open drain plate 5|, and into the sink the loose 9 rough food particles on the dishes. This prerinse operation also serves as atempering agent gradually bringing the dishes up to a proper washing temperature.

The drain plate isthen closed by the knob a l and proper temperature hot water is permitted to enter the tank It! until it starts to overflow through the overflow tube 46, which overflow is detected by means of the audible overflow indicator previously described. The faucet water is then shut off and the motor timer clock switch is turned on and set for a five minute interval by means of the knob I29 and rod I28.

The detergent knob 65 is then pulled up tripping the cup 95, the action of which ejects the cap 58 and permitting the detergent to be spilled into the surge stream.

The motor 68 through the shaft SI rotates the impeller ll; causing a surge and spray of water upwardly and outwardly in varying oscillating angles, over, under and along the sides of the dishes and silverware. The food particles thus washed from the dishes being trapped in the sediment screen 8!} as hereinbefore described.

At the termination of the five minute interval, the timer it! shuts ofi the motor 60 and the operator then opens the drain plate 5| allowing the dirty water to be discharged through the telescoping tube 53 into the sink at the same time flushing the sediment screen. The operator then closes the drain plate 5! and opens the hot water tank as before until a suitable water level is obtained as indicated by the audible overflow indicator previously described.

The motor timer is then set for a one minute interval providing an impeller surge rinse. At the end of the one minute interval, the motor is automatically turned off. The operator then opens the drain plate 5! allowing the'first after rinse water to discharge as before.

The operator then turns on the hot water with the drain plate 5| open for approximately 3i) seconds to provide a second after rinse. This second after rinse knocks oil the last remaining food particles resulting in a particularly ehicient dish washing and rinsing operation heretofore unobtainable in conventional domestic dish washing machines.

The immersion heating element 87 is used as a booster for the water temperature where the washing or rinsing water from the faucet is below the temperature required for proper dish washing operation, and is also used to stimulate the action of the bi-nietal which in turn effects the impeller blades. The heater timer clock i313 is adjusted from the front of the dish washer base for needed time intervals according to the operators desire.

During the pre-rinsing, the washing operation, and the two after rinses the rotatable racks Sill, 9s, 9i and ill! are constantly oscillated and change tilted by means of the bi-metal coil H3 and its linkage previously described.

After the rinsing has been completed, the operator drops the front wall [6 and the dishes are permitted to dry from the heat stored in them. The racks containing the dishes may then be removed from the tank and placed in the cupboards, or elsewhere for storage. With multiple sets of racks and trays, the dishes may be left in them in the cupboards and succeeding batches of dishes may be washed and stored conveniently.

Pots and pans may be washed in this machine by leaving out some or all of the racks and resting the pots and pans on the tank bottom where they are held in position by means of the rods 93 and I00.

At the close of the above operation, the hose fitting 32 is disconnected from the faucet and coiled on hook l4, and the extension cord 29 is disconnected from the outlet and coiled on the hook E5. The brake 25 is then released and the dish washer may be rolled on the ball casters 2! to the back of the counter top or elsewhere out of the way until it is desired to use it again.

Having described my invention, what I claim and desire to secure by Letters Patent is:

l. A dish washing and rinsing machine of the character described comprising a tank having cambered side Walls and top, a hopper like bottom, said top having a centrally positioned motor compartment, a motor in said compartment, and a variable pitch blade impeller mounted for rotation on said motor, said impeller being connected by intermediate linkage to a bi-metal element which is actuated by the change in temperature of water surrounding it, whereby on the flexing and unrlexing of said bi-rnetal element the pitch or" said impeller blades is changed.

2. The combination defined in claim 1, including a heating element located in close proximity to said impeller.

3. A dish washing machine comprising an elongated tank having a cambered side wall and top, a hinged drop open cambered front wall and a hopper like bottom having a sump therein, means for opening and closing said sump, a motor driven variable pitch impeller mounted above said sump, a bi-metal element connected to said impeller by intermediate linkage, and a heating element positioned in said tank adjacent said impeller, and arranged to actuate said bi-metal element, whereby upon the flexing and unrlexing of said bi-metal element the pitch of said impeller blades is changed.

4. The combination defined in claim 3, including a plurality of removable racks oscillatable about one axis and tiltable about a different axis, positioned in said tank within the surge area of said impeller.

5. A dish washing machine comprising a tank having elongated cambered wall and top, a hinged drop open cambered front wall and a hopper like bottom, water connections for introducing water to said tank including a plurality of overhead positioned nozzles, a plurality of trays, each oscillatable about one axis and tiltable about another, positioned in the spray area of said nozzles, means for oscillating and tilting said trays, and a motor driven impeller positioned in said tank and arranged to direct a changing pattern surge of water into and about said trays.

6. The combination defined in claim 5, in which there is a bi-inetal element arranged to change the pitch of the blades of said impeller, a heating element positioned in said tank adjacent said impeller and arranged to actuate said bi-metal element.

'7. The combination defined in claim 5, in which there is a sump positioned in said bottom, said sump having a removable cover plate with externally controlled means for operating the same.

8. The combination defined in claim 5, in which there is a sump positioned in said bottom, said sump having a removable cover plate with externally controlled means for operating the same, and a non-clogging variated mesh sedi- 7 11 ment screen secured to said cover plate, said screen having see-saw side walls and a drop apron.

9. The combination defined in claim 5, in

V which there is a detergent carrying vehicle positioned in said tank, and arranged to discharge a detergent into the water surge of said impeller, there being means positioned on the exterior of said tank for actuating said detergent vehicle.

10. A dish washing machine comprising an elongated dish receiving tank, a motor chamber in the upper center of said tank, a motor in said chamber, a two bladed variable pitch impeller mounted for rotation on the shaft of said motor, a bi-metal element for varying the pitch of the blades of said impeller, a plurality of removable racks, each oscillatable about one axis and tiltable about another, positioned about said impeller, and overhead spray means for directing water sprays over and about said racks.

11. The combination defined in claim 10, including means for maintaining a predetermined water level in said tank, and. a heating element positioned in the bottom of said tank and arranged to change the temperature of the water immediately surrounding said impeller.

12. The combination defined in claim 10, including means for oscillating and tilting said racks, and means connecting at least one or" saidracks to the overhead spray means whereby the latter will oscillate in unison with said racks.

13. A dish washing machine comprising a dish receiving tank, a motor centrally positioned in said tank, said motor having an impeller mounted for rotation therewith, a plurality of shallow dish receiving racks each oscillatable about one axis and tiltable about another, a multiple cone and fan spray nozzle and pipe assembly positioned for directing an overhead spray on to and about said racks, a bi-metal member for rotating and tilting said racks, a heating element positioned near said bi-metal member, and an externally controllable timing means for operating said heating element.

14. The combination defined in claim 13, including a linkage from at least one of said racks to said nozzle and pipe assembly arranged to oscillate said nozzle and pipe assembly in unison with said racks.

15. A dish washing machine comprising an elongated cambered tank, an electric motor positioned in said tank, said motor having a two bladed variable pitch impeller mounted for rotation therewith, heat responsive means for changing 12 the pitch of the blades of said impeller, electrical means for controlling the operation of said motor, a heating element in said tank adjacent said impeller and timing means for controlling the heating of said heating element.

16. A dish washing machine comprising a tank having an electrically operated impeller therein, a heat responsive element for changing the pitch of the blades of said impeller, and electric heating element for actuating said heat responsive element, water intake means for said tank, said water intake means including an anti-friction pressure spring loaded valve having a bypass element and a flexible metallic inlet hose connecting said valve to said tank, said flexible metallic hose serving as a ground for the electric elements of said machine.

17. A dish washing machine comprising an elongated tank having a cambered side wall and top and a hopper like bottom, handles on the end walls of said tank, a hinged cambered drop open front Wall having a drip bafile associated therewith, a spherically terminated, vertically elongated motor chamber secured in the top of said tank, a vented cover plate for said motor chamher, an electric motor mounted in said chamber said motor chamber being spherically terminated at the lower end thereof, and an impeller mounted for rotation on the shaft of said motor.

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